Wie viel von den Texten dieses Liedes kann jemand, der Armenier kennt, verstehen?

This is Hemshin dialect of Armenian, which is very distinct from other Armenian dialects due to isolation. So most Armenian speakers who dont speak this dialect will understand some words but not the entire song. For example, I’ve heard ‚lusin‘, ‚gisher‘, ‚es‘ and my Armenian is not at the native level.

Native western armenian speakers will understand probability half or most of it on the first try but not all that dialect is too distinct. If they get more exposure they will understand it. 

Eastern armenian speakers will hardly understand anything other than few words and the grammar and loan words are also way harder. Western and Eastern armenian have different grammar anyway part that with a distinct difficult accent and unfamiliar loan words and you’ll have troubles making sense of whats being said

Native eastern speaker, I understand words here and there, can put them together to understand some sentences. So I’d say about 15-20%

It’s basically like hearing Ukrainian as a Russian speaker.